Semiconductor devices are fabricated by processes that involve depositing, patterning, and removing of materials on substrates. Deposition processes such as chemical vapor deposition (CVD) or physical vapor deposition (PVD) may be used to deposit a layer of material on a substrate. Photolithography techniques may be used to create a pattern on a layer of material to control where etching, depositing, or implanting will occur.
Etch processes may be used to remove portions of a deposited layer, so that other materials may be deposited in the removed portions. Ion implantation processes may be used to change the properties of a deposited layer of material by physically bombarding and implanting dopants into the deposited layer. By using various ones of these process steps, semiconductor devices, and, thus, integrated circuits are created on the substrate.
In fabricating integrated circuits (ICs), specialized process chambers are used sequentially to perform the steps required to build the semiconductor devices and the ICs. Each chamber usually has an inner chamber in which predefined conditions, such as a certain vacuum level, are maintained during the process.
For a complex integrated circuit, hundreds of individual process steps may be involved in building and interconnecting all of the underlying semiconductor devices. To streamline the manufacturing process, process chambers may be integrated into a cluster tool, so that the different process steps may be executed sequentially and efficiently, using less factory space than stand-alone chambers, and requiring less distance to transport wafers from process step to process step. A cluster tool provides process sequence integration by “clustering” several different process chambers into one platform.
In some inspection tools and process chambers a device such as a substrate is moved along various directions during the inspection, metrology or manufacturing process, respectively.
The inspection/inspection tool/process chamber has a chamber in which various predefined conditions such as a certain vacuum level are maintained. When some processing chambers are integrated into a cluster tool the substrate may be shifted from one process chamber to another without the need to break pressure seals in the process environment.
As a result, there may be fewer opportunities for unwanted contamination to occur. In addition, it is possible to save some or all of the time involved in completely venting a chamber, moving a substrate from stand-alone chamber to stand-alone chamber, and then pumping down each succeeding chamber to achieve the necessary level of vacuum to conduct the next process sequence.
Because of the complexity of the manufacturing process, there is frequent inspection of substrates to ensure that the process steps are executed property and that the substrates are reasonably free of defects, preferably as free of defects as is practicable. Currently, processing and inspection/metrology of semiconductor substrates are done separately, in stand-alone tools.